Stevie Nicks had hoped to visit Christine McVie during her illness, but couldn't make it to London before Christine passed away.

Nicks addressed the passing of her longtime Fleetwood Mac bandmate Thursday afternoon, shortly after news of Christine's passing was released.

"I didn't even know she was ill until late Saturday night," Nicks wrote. "I wanted to be in London, I wanted to get to London — but we were told to wait."

Christine's family said in an announcement that the singer-songwriter was "in the company of her family" at the hospital Thursday morning when she passed away "peacefully ... following a short illness."

Nicks described Christine as her "best friend in the world since the first of 1975" (when she joined Fleetwood Mac). She explained that since she learned of her fellow Rock and Roll Hall of Famer's illness "one song has been swirling around in my head, over and over. I thought I might possibly get to sing it to her, and so, I'm singing it to her now."

Nicks finished her note with some lyrics from Haim's "Hallelujah":

"I had a best friend but she has come to pass

One I wish I could see now you always remind me

That memories will last these arms reach out

You were there to protect me like a shield

Long hair running with me through the field

Everywhere

You've been with my all along

Nicks signed her note, "See you on the other side, My Love. Don't forget me. Always, Stevie."

In an interview given this past summer, Christine admitted that while she and Nicks were virtually inseparable on the last Fleetwood Mac tour, they had scarcely communicated since the tour ended.

Fleetwood Mac issued a statement Thursday addressing Christine's passing:

"There are no words to describe our sadness at the passing of Christine McVie," the band said in a release. "She was truly one-of-a-kind, special and talented beyond measure. She was the best musician anyone could have in their band and the best friend anyone could have in their life. We were so lucky to have a life with her. Individually and together, we cherished Christine deeply and are thankful for the amazing memories we have. She will be so very missed."